The present invention generally relates to activation control of storage devices.
In recent years, an amount of data handled in the distribution industry and the financial industry has been being increasing daily. As the amount of data increases, the scale of a storage device group (one or more storage devices) is being enlarged and the power consumption by storage device groups is increasing. Therefore, there is a demand for a technique that implements, for example, accumulation and analysis of big data with low power consumption.
There is a spin-down technique for hard disk drives (hereinafter referred to as the HDDs) as an example of low power consumption techniques for the storage device groups. The spin-down technique is a technique that reduces the power consumption by reducing the speed of, or stopping, the revolutions of the disks. However, if the HDDs in a spin-down state is spun up, the power consumption of the HDDs temporarily increases considerably. If the HDDs in excess of a certain quantity are spun up simultaneously under this circumstance, there is a possibility that the power consumption may exceed its upper limit.
There are techniques disclosed in, for example, JP4642347 and JP2010-003149 with respect to this problem. JP4642347 discloses a technique that shifts an activation order of HDDs. JP2010-003149 discloses a technique that calculates the power consumption when activating HDDs of a certain RAID (Redundant Array of Independent [or Inexpensive] Disks) group and shifting the activation order of the HDDs as necessary.
Furthermore, since it takes time to spin up HDDs from its start to its completion, I/O (Input/Output) to the HDDs in a low power-consumed state requires some time. There is a technique disclosed in JP2009-080603 with respect to this problem. JP2009-080603 discloses a technique that activates the HDDs in the low power-consumed state in advance on the basis of I/O history for the HDDs.